THe rams are large enough that they are easy to sex and have great color. About 1.2 to 1.5 inches for the males and about 1 to 1.3 for the females.
The black banded sunfish come from the swamps of the east cost of the US. They need soft slightly acidic water, that is normal water from a swamp, but can handle temperatures from 32F to probably the 90s. They are not that aggressive, they tend not to eat their own fry and I have tried to feed them baby swords, but they did not eat them. Black banded sunfish would do well in the typical planted tank where the plants are growing well.